Oct. 4, 2011-- If smoking is not controlled worldwide, the habit could produce 18 million new tuberculosis (TB) cases and 40 million deaths from TB between 2010 and 2050, according to a new study.

Tobacco and tuberculosis are linked, with tobacco smoking a risk factor for the disease.

The research is published online in the journal BMJ.

Researcher Sanjay Basu, MD, PhD, and his team created a mathematical model of TB epidemics. They wanted to compute the impact of tobacco on TB cases and deaths.

They plugged in the incidence of TB and deaths from it. They took into account changing trends in smoking, TB treatment, and other factors.

The completed model predicted that smoking, if not controlled, could produce the 18 million new TB cases and 40 million TB deaths. The number of TB cases would rise by 7%, from 256 million to 274 million. The number of TB deaths would increase by 66%, from 61 million to 101 million.

Global Smoking Rates

Nearly one-fifth of the world's population smokes, the researchers say. A moderate increase in individual risk, in this case, translates to a large risk in the population because so many people smoke.

The areas most likely to be affected by new TB cases linked to smoking include Africa, the Eastern Mediterranean, and Southeast Asia.

The researchers also estimated the effect of decreasing the use of tobacco. If smoking rates were aggressively lowered, the TB deaths linked to smoking could decrease by 27 million by 2050. Aggressive lowering was defined as a decrease of 1% per year, until smoking is eliminated.